Regulatory Tissue Polymorphonuclear Leukocytes Determinants of Ocular Immune Responses

 描述(申请人提供)：在眼免疫反应的病因或发病机制中，多形核白细胞(PMNL)在很大程度上被忽视。PMNL推测眼睛的作用是宿主防御，它们被认为是二次招募的促炎细胞，导致下游侧支组织损伤。然而，单一原始炎症性PMNL细胞类型的教条在其他器官系统中迅速演变，现在已认识到调节淋巴细胞功能的不同PMNL群体。泪液缺乏性干眼病是一种免疫诱导性眼病，其发病机制是由效应器T细胞的异常激活引起的，是最常见的眼病之一，在女性中有显著的发病率。PMNL在干眼病中的作用尚未被研究。PMNL的主要功能是形成和释放二十烷基类化合物，这些脂质介质的受体在淋巴细胞中表达。然而，二十烷类化合物对淋巴细胞的调节是一个相对未被探索的免疫调节领域。除了驱动宿主防御外，PMNL也是产生抗炎二十烷基脂蛋白A4(LXA4)的限速细胞类型。 我们最近首次提供了人类和小鼠角膜损伤反应在性别上存在显著差异的证据，并确定雌激素下调上皮性LXA4回路是女性伤口延迟愈合的机制。在初步研究中，我们在健康男性和女性的角膜缘、泪腺和颈部淋巴结中发现了一种新的产生LXA4的组织PMNL群体。这种组织PMNL与炎症性PMNL不同，它表达一个高度放大的LXA4电路，并在免疫驱动的干眼病期间受到动态和性别特异性的调节。最显著的性别差异是，与男性不同，女性的干燥压力引发了淋巴结PMNL数量的显著下降，而在干眼病期间，PMNL数量仍然处于低迷状态。女性淋巴结PMNL下降与LXA4形成减少和早期激活的CD4+T细胞增加直接相关，并与干眼发病有关。重要的是，我们在引流淋巴结的T细胞中发现了LXA4受体ALX的动态表达。这些开创性的发现激发了三个具体的目标：i.确定LXA4产生组织PMNL和LXA4在免疫驱动的干眼病中在眼表和引流淋巴结中的作用。II.利用新型ALX KO-GFP启动子报告鼠系，阐明组织PMNL和LXA4受体(ALX)介导的抑制效应T细胞活化的机制。III.研究性类固醇在雌性特异性调节LXA4产生中的作用 并通过蛋白质组学和脂体学方法确定招募这一新的PMNL群体的因素。该项目的目标是研究组织PMNL、LXA4及其受体在免疫驱动的干眼病中的作用，并建立它们的性别特异性调节作为女性异常效应器T细胞激活和启动眼部疾病的重要因素和治疗靶点。

 DESCRIPTION (provided by applicant): Polymophonuclear leukocytes (PMNL) have largely been ignored in the etiology or pathogenesis of ocular immune responses. PMNL presumed ocular role is host defense and they are considered secondary recruited pro-inflammatory cells that cause downstream collateral tissue damage. However, the dogma of a single primitive inflammatory PMNL cell type is rapidly evolving in other organ systems and distinct populations of PMNL are now recognized that regulate lymphocyte function. An immune-driven ocular disease, whose pathogenesis is initiated by aberrant activation of effector T cells, is aqueous tear deficient Dry Eye Disease, which is one of the most frequent ocular morbidities and has a striking female prevalence. The role of PMNL in Dry Eye Disease has not been investigated. A primary function of PMNL is formation and release of eicosanoids and receptors for these lipid mediators are expressed in lymphocytes. However, eicosanoid regulation of lymphocytes is a relatively unexplored area of immune regulation. In addition to driving host defense, PMNL are also the rate limiting cell type for generating the anti-inflammatory eicosanoid lipoxin A4 (LXA4). We recently provided the first evidence for marked sex-specific differences in corneal injury responses in both humans and mice and identified estrogen downregulation of an epithelial LXA4 circuit as a mechanism for delayed wound healing in females. In pilot studies, we discovered a novel LXA4-producing tissue-PMNL population in corneal limbus, lacrimal glands and cervical lymph nodes of healthy males and females. This tissue-PMNL, unlike inflammatory-PMNL, express a highly amplified LXA4 circuit and are dynamically and sex- specifically regulated during immune-driven Dry Eye Disease. The most striking sex-specific differences was that desiccating stress in females, unlike in males, triggered a remarkable decrease in lymph node PMNL numbers that remained depressed during Dry Eye Disease. Depressed lymph node PMNL in females correlated directly with decreased LXA4 formation and an early increase in activated CD4+ T cells and dry eye pathogenesis. Importantly, we identified dynamic expression of the LXA4 receptor, ALX, in T cells from draining lymph nodes. These ground breaking findings inspired three specific aims: I. Establish the role of LXA4- producing tissue-PMNL and LXA4 in the ocular surface and draining lymph nodes in immune-driven Dry Eye Disease. II. Elucidate the mechanism for tissue-PMNL and LXA4 receptor (ALX) mediated suppression of effector T cell activation using a novel ALX KO-GFP promoter reporter mouse line. III. Investigate the role of sex steroids in the female specific regulation of LXA4-producing PMNL and identify factors that recruit this novel PMNL population by proteomic and lipidomic approaches. The goals of the project are to investigate the role of tissue-PMNL, LXA4 and its receptors in immune-driven Dry Eye Disease and establish their sex-specific regulation as a significant factor and therapeutic target in aberrant effector T cell activation and initiation of ocular disease in females.